1. Field of the Invention
The invention relates to a heat exchanger, a heat-exchange reformer in which the heat-exchanger is used, and which generates hydrogen by reforming a raw material, and methods of producing the heat exchanger and the heat-exchange reformer.
2. Description of the Related Art
A cross-flow fuel reformer is available. In the cross-flow fuel reformer, a plurality of plates are stacked. Each of reforming passages is formed between the plates, and each of heating passages is formed between the plates. The reforming passage and the heating passage are adjacent to each other via the plate. In the reforming passage, a hydrocarbon raw material is reformed to generate hydrogen-containing gas. In the heating passage, fuel gas is burned to supply heat to be used for a reforming reaction in the reforming passage. Such a fuel reformer is described, for example, in Japanese Patent Application Publication No. 2004-244230 (JP-A-2004-244230).
However, in the above-described fuel reformer, when manifolds are provided to distribute gas to the plurality of reforming passages and heating passages, and collect gas from the plurality of reforming passages and heating passages, rectangular-cylindrical manifold members are joined to end surfaces of the stacked plates. The uppermost plate, lowermost plate, and the like, to which the manifold members are joined, need to be thick. With this configuration, heat transmission passages, through which heat is transmitted from the thick plates to the manifold members, are formed. Part of heat generated in the heating passages is radiated via the heat transmission passages, and is not consumed in the reforming passages. This causes heat loss.
U.S. Pat. No. 4,776,387 A discloses a heat exchanger with a stacked core. The stacked core comprises channelized layers forming a first and a second heat-exchange passage. A case houses the stacked core such that a first heat-exchange medium and a second heat-exchange medium flow into and flow out of the stacked core by the heat-exchange passages. The core is fastened in the case by springs. In order to reduce the amount of heat that the springs are subjected to the first channelized layer next to each solid outer face of the core is sealed so that no gas passes through said layer. This, however, reduces the amount of heat exchange. Further, the channelized layer is provided only on the two solid faces of the core. The remaining four faces do not comprise a a heat-insulation layer. This causes heat loss on this faces.